


Charles' Law

by xenobia4



Category: Numb3rs (TV)
Genre: Brother/Brother Incest, Choking, Drunk Sex, Drunkenness, Incest, Light BDSM, M/M, Sibling Incest
Language: English
Status: Completed
Published: 2021-02-26
Updated: 2021-02-26
Packaged: 2021-03-17 00:20:54
Rating: Mature
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 2,834
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/29708769
Author URL: https://archiveofourown.org/users/xenobia4/pseuds/xenobia4
Summary: Don acts on Charlie's confession, consequences be damned.
Relationships: Charlie Eppes & Don Eppes, Charlie Eppes/Don Eppes
Comments: 2
Kudos: 10





	Charles' Law

**Author's Note:**

> I have no regrets.

**Charles' Law**

“To get that perfect carbonation, you have to realize that the total pressure is equal to the sum of the partial pressures exerted. So for the process of brewing the perfect beer, you only need to consider Dalton’s Law,” Charlie finished, his eyes bright as he focused his attention on the bottle of beer in his brother’s hand.

The corner of Don’s eyes crinkled as he laughed and took another sip, now on his fifth bottle.

Charlie had gone from Don’s bottle to his own, which was his third, now half-empty. He went into the mathematical equation of carbon dioxide, explaining how the CO2 effected the bloodstream much faster than that of hard liquor. Carbon dioxide caused the absorption to amplify. While liquor would last longer in the system, carbonated beverages would hit faster, though metabolize quicker. Listening to his brother ramble on about math he could not even comprehend, Don just laughed and nodded, occasionally agreeing or commenting the simple, “Is that right?”

As Charlie fell into the mathematical equations, Don found himself watching him, his expression becoming one of fondness and familiarity. Even when he could not understand what was coming out of his brother’s mouth, seeing him light up always caused a warmth to build across his chest. The way Charlie’s eyes would brighten, the way his movements would become sporadic and excited, how he would lose himself in his tangents, smiling wider with each passing second. Perhaps it was the alcohol in his system, but Don could not help but realize the attractive young man his brother had grown into being.

It made him chuckle every time they would go out to lunch and the way both women and men would flirt with his little brother. All the while, Charlie was completely oblivious, always losing himself in his numbers over either whichever class he was teaching or case he was assisting Don and his team with. Each time, there was always a flare of jealousy – whenever a fellow agent’s hand would linger a little too long on his shoulder, or when a server would smile a little too brightly at him, or when strangers would touch his lower back as they walked by.

Just the other day, Charlie had stopped by the bullpen to drop off his findings on a string of bank robberies. Don walked him to the elevators, thanking him for his help as Charlie was leaving to go back to CalSci. He was only a few steps away, heading back to his office, when an agent had approached before the elevator doors shut and asked Charlie out on a date. Don had done a near 180°, sending the male agent a disbelieving, yet threatening, look. It was not so much as a man asking the young mathematician out, but because it was _Charlie_ – his little brother. And this agent was not only trying to get with his little brother, but they had the gall to try before Don was even out of earshot. Charlie’s face had flushed red as he turned him down, clearly feeling awkward as he waited for the elevator doors to close. Once they were, the agent turned to go back to their desk, only to find Don staring him down.

“Yeah, that’s all well and good, but you’re forgetting one key point,” Don said as Charlie finished his rambling. Charlie gave him a confused look, his mind clearly going over the math he had been going on about. “We’re empty,” he smiled as he motioned to both their now-empty bottles.

Charlie’s expression fell to a frown, as though realizing Don had not actively been paying attention to anything he had been saying. Releasing a sigh, he glanced to the bottle he was still holding. With an annoyed look to his older brother, he stood up, stumbling slightly as Don handed him his own empty bottle. He disappeared into the kitchen. Don sank into the couch, allowing his head to fall back on the cushions, the weight of six beers causing his head to feel light. He could hear Charlie in the kitchen, the two bottles clinking against the others in the trash bin before the fridge door opened.

A moment later and Charlie was passing him another beer from the back of the couch, which Don dutifully accepted. He took a sip and watched his younger brother take a seat back in the chair.

“Hey, Chuck, can I ask you something?”

“As long as you don’t call me that, sure.” He drank from his own bottle.

Don laughed at the response. “The other day with Finer”—Charlie nearly choked on his beer, recalling the incident by the elevator—“did you actually consider taking him up on it?”

“What?! No, no! He’s – I’m – it’s—” he became frantic, stumbling over his own words as he became focused on the label to the bottle. Don raised his brows in amusement. “Look, Don, he’s not really my type, you know? A little too—”

“Manly?”

“—effeminate.”

Both of their responses seemed to have caught each other off-guard.

Don knitted his eyebrows as he watched his brother’s posture change. He had gone from frantic to nervous, his fingers peeling away at the label and littering his lap with small pieces of paper.

“Charlie, are you…gay?” Don asked bluntly, leaning forward and setting his elbows on his knees.

“I believe the correct term is bisexual,” Charlie laughed awkwardly before clearing his throat and shedding more of the paper. “I mean, attraction is relative. Physical attraction, even, is all about ratios and symmetry. The Fibonacci Sequence has proven that we instinctually look for the Golden Ratio in people we deem attractive – physically or otherwise. Male or female, there are key differences on why we find certain types of women attractive, while what we find attractive in the male body varies, and—”

“Charlie, Charlie,” Don called, getting his brother to fall silent, his eyes still focused on the bottle, purposefully ignoring his older brother’s gaze. “You don’t have to explain it to me, all right?” He still tried to gain Charlie’s attention, but was either ignored or unheard. Sighing, Don took to his feet and walked to the chair, sitting down on the arm. After a quick glance to Charlie, he focused on his beer and took a sip. “So…what is your type when it comes to men? I mean, it’s clearly not Finer,” he said with a light laugh, recalling the agent’s tall and lanky stature, trying to get Charlie to loosen up.

Charlie’s forehead creased, his brows moving upwards in the fear of uncertainty.

“Personality-wise? Strong, authoritative, the ability to command. Physically?” he paused for a moment, his eyes darting to Don before falling back on the bottle, which he took a swig from. “Taller, athletic build, preferably brunettes…,” he trailed off, seeming to curl in on himself.

As Don was drinking his beer and nodding, the realization seemed to hit him and he pulled forward. Charlie’s eyes were wide while still managing to remain attentive to the various flakes scattered on his lap and the floor. He turned his head towards his brother, a confused, yet surprised, expression on his face. “You’re not talking about—”

“It’s – I’m – you see, the thing is, it’s how you – and it’s not that it’s—”

“Charlie, shut up.” In an instant, Charlie closed his mouth, eyes staring beyond the bottle and hands shaking. Don released a sigh and took a rather large swig, short of chugging the entire beer like a college frat boy. He looked at Charlie. The younger man was tense, his breath fast as his face bled red, his eyes glistening. “You know we’re drunk, right?” he asked as he finished off what little was left. Out of the corner of his eye, he saw Charlie’s head nod slightly. Don mirrored the nod and leaned forward to set his bottle on the table. “Hey, look at me,” he said, a little more commanding than he meant to.

Nerves wracking his body, Charlie slowly turned his head to look up at where Don was sitting on the chair’s forearm, his eyes large and bright, full of ambiguity. Foregoing any logic in his brain, Don found himself leaning down and pressing lips against Charlie’s. The shock had Charlie drop his beer.

It hit the floor with a thud, the liquid seeping out onto the hardwood.

His heart pounding in his chest should have been the key to stop, but instead, Don held Charlie’s face with his hand. Charlie’s came up to grab it, pulling back ever-so slightly.

“Don?”

“We’re both drunk. Things happen.” Charlie nodded as Don began kissing his jaw, moving down to his neck. “If you want to stop, we will.” Charlie swallowed and shook his head. Don chuckled and lightly bit the skin, causing Charlie to jerk.

This was so wrong on so many levels.

But for some reason, with now-seven beers swimming through his system, and Charlie’s scent filling his nostrils, he did not care.

They managed to make their way to the couch, Don stripping off his button-down and Charlie his t-shirt. As one arm wrapped around Charlie’s thin waist and his hand holding his cheek, his mouth trailed from Charlie’s jaw to his collarbone. He could hardly register how small his brother felt underneath him. Even when Charlie wore more “professional clothes”, they were always a size too large, and it had never occurred to Don that perhaps Charlie was trying to make himself appear bigger than he was.

Charlie’s hands were shaking on his arms as they ran over his biceps and triceps. Don was not quite sure what he was doing, but he seemed to be doing something right when he ran his tongue over a nipple and Charlie twitched and gripped his arms. It made him wonder what else his younger brother liked, but when he rubbed their groins together through their jeans garnering a whimper, several ideas ran through his head.

The alcohol running through his system, the understanding that Charlie was fairly attractive, the way his brother drew other peoples’ attention without realizing it – the barrage overflooded and Don found himself pushing Charlie back on the couch, covering his body with his own. Something about taking the person people would throw themselves at and still be denied made him want to take Charlie completely.

Charlie did not seem to know what to do with his hands as Don’s tongue flicked over his nipple and his left hand twisting the other. His hands went from his brother’s short hair to his shoulders, back to his hair before grabbing the edges and cushions of the couch. Don could not help but grin when he moved lower, tracing soft kisses and sucking on his younger brother’s chest and abdomen. When he dipped his tongue into Charlie’s navel, and his brother’s reaction was a shout and hand jerking up grab a fistful of Don’s hair, he grabbed Charlie’s wrist and pinned it down. Making his way to the waistband of Charlie’s jeans, the younger man began squirming beneath him.

Don did not need to use his hands to undo Charlie’s button and zipper, years of experience on both ends of the spectrum taking over. It was at that moment Charlie wrestled his hand free and wound up covering the growing outline in his briefs.

“Don! Wait wait wait!” he cried out, his face red and unnoticed tear lining his temples as he pulled up. “Y-you’re drunk and tomorrow—”

He was cut off by Don capturing his lips and tongue exploring his mouth. Charlie’s hands went from hiding himself to moving to his brother’s shoulders, whimpers escaping his throat as the reality of what they were doing set in.

“And tomorrow, I’ll love you just as much,” Don whispered as he pulled back, hands cupping Charlie’s face. He nipped at the other’s bottom lip, giving the reassurance Charlie was in desperate need of.

Don reached down and batted Charlie’s hands away from hiding himself. Reaching his hand underneath the fabric of his boxer briefs, he began touching his younger brother’s length, teasing the tip before wrapping his hand around the base and stroking him. Charlie released a moan and Don pressed his mouth against his brother’s exposed neck, sucking on the sensitive skin to form a dark bruise. The stubble against his lips and nose caused his own knob to twitch at the realisation he was about to delve into his little brother’s darkest desires and, at the same time, his own.

He formed another bruise on Charlie’s Adam’s apple, kissing and licking it as he pushed Charlie’s jeans and briefs down his thighs, exposing his younger brother’s body. Don dipped down, kissing his brother’s inner thighs before his tongue darted out to lick his hole. The minor stimulation caused Charlie to jerk and release a cry, his hands grabbing the fabric of the couch.

It was his reaction that had Don realise his little brother never had a true experience and he would be Charlie’s first. He grabbed Charlie’s legs and pushed them back, forcing them to his brother’s head and exposing his area, opened and inviting. “Hold your legs up,” he said, voice coming out more commanding than his meant. It worked and Charlie, despite feeling nothing but confusion and desire, did as he was told, completely exposing himself. Don took the invitation and inserted his tongue, circling it within the ring and gaining a mixture of cries of moans from his brother.

As Charlie’s voice bounced around the living room, Don reached his hand up to Charlie’s neck and grasped his throat, squeezing until his little brother’s cries sounded drowned and choking. When the younger man’s hands grabbed his wrist to pull him off as the lack of air sent him into fight or flight, Don pulled up, pressing his hand down harder on the other’s throat as he leaned down to capture Charlie’s lips. His hand had gone from cutting off Charlie’s air to grabbing his jaw, his lips and tongue forceful into his brother’s mouth.

Pulling back just enough to speak, he breathed into Charlie’s mouth, “I’m gonna fuck you so goddamn hard,” before forcing his mouth back down.

Reaching down his free hand, he removed his own knob from the confines of his jeans and pressed it against Charlie’s now-slicked hole. With the alcohol swimming through his system and his younger sibling’s, the logic that saliva would be enough to hold up burrowed its way into his head and he pressed his knob into his younger brother. His hand pressed harder on Charlie’s throat as he slid his length completely inside, watching has Charlie’s eyes began to roll back into his head. As he began to thrust in and out, he abandoned his grip on his brother’s throat, who took in a large gasp of air before falling into a round of cries.

“God, you’re fucking beautiful, Charlie,” he moaned as he grabbed Charlie’s ankles and pushed his brother’s knees to his ears. When Charlie’s hands went to his shoulders and chest, Don’s thrusts became faster and harder, slamming into his brother as Charlie’s cries echoed around them, along with Don’s moans and grunts. “Touch yourself, touch yourself, cum for me,” Don found himself saying.

Charlie did as he was told. With one arm wrapping around Don’s shoulders, his free hand wrapped around his own knob and he began rubbing himself in-tune with Don’s thrusts, crying as Don began hitting his prostate on each pass. It did not take long for Charlie to begin moving his entire body with Don’s movements, a loud shout echoing around the living room as Don buried his entire length inside him. It did not take much longer for Charlie’s body to give way. He shuddered and tensed as he came, thick ropes shooting onto his stomach and chest as he kept his pace with his brother’s thrusts.

Don was not far behind him, feeling Charlie contract around his knob as he came. He did not mean to ejaculate inside his brother, but the sensation was too much and he found himself pumping hot liquid deep into him, moaning as he did. Don bent down, capturing Charlie’s mouth in an aggressive kiss as he pressed every bit of himself into his little brother, the euphoria of ecstasy and taboo drilling through his veins.

He collapsed on the younger man, their chests heaving against each other’s.

Charlie’s legs dropped, draping against Don’s thighs as Don set his head on Charlie’s chest, listening to his little brother’s heartbeat.

Nothing about what they had done was right, but in the aftermath, everything felt as though it was. Don wrapped his arms around Charlie’s lithe body and Charlie returned the sentiment by resting his head on his older brother’s.

Taboo though it might have been, in the moment, there were no concerns. And both of them were certain the moments would come again, sobriety or not.

**Author's Note:**

> Please comment if you enjoyed! This was fun writing!


End file.
